Duplex board



B. K. FORD.

DUPLEX BOARD.

APPLICATION FILED wuss. 1919. 7

1 ,345,081. Patented 311116.29, 1920.-

ameml oz ing and the adjacent face of theother being BEN K. roan, or nAs'r omnen, new masnr.

DUPLEX 7 BOARD.

Specification of Letters Patent. Patented J 11119 29, 1920.

Application filed June 5,, 1919. Serial No. 302,010.

To all tohom it may 'coacern: Be it known that I, BEN K. Fonn, a citizen of the United States, and residing at East Orange, in the county of Essex and State ofNew Jersey, have invented a new and Improved Duplex Board, of which the following is a specification.

This invention consists in a two ply board formed ofpaper of any desired character,

one of the plies being givena preliminary a fusible substance such as ascoating of rubber, shellac or resin, whlch phalt, tar,

has been permitted to cool and set, one face of the other ply being coated with a cement of any desired character before being brought into contact with the coated face of the first ply, the two coated faces being It also consists in applyin finely comminuted material such as wood or grain flour, to the fusible coatbefore it becomes hard, should this fusible material be of such a character that the cement on the second ply will not adhere thereto.

In the accompanying drawings, Figure 1 illustrates a duplex board formed of two plies, one of the plies having a fusible coatcoated with a cement. Fig. 2 1s a similar view showing the fusible coat powdered with a substance to which cement .will' freely adhere.

Similar reference characters refer to like parts throughout the several views. It has been foundthat when the severa plies of paper or straw board containers are secured to ether by a dissolved cement, such as glue, t at the container is not impenetrable to vapors and gases. The minute passages through which the solvent of the cement escapes while the cement is drying permit the escape of moistures in the contents of the container. To overcome this difliculty, one of the plies forming such containers is often of duplex board, consisting of two thicknesses of paper secured together by a fused cement, such as asphalt or tar,

which penetrates and fills all the minute passages in the board, making it substantially vapor and gas proof.

he objection to this material is that containers cannot be readily produced on s iral tube winding machines of only two t icknesses as the du lex board must be made up in advance an constitutes oneof the two plies.

pressed together to cause the plies to adhere.

. mandrel.

I have found that I can coat one side of .any ordinary fibrous board 1 (Fig.1) such as is used in making containers with a layer of hot melted asphalt, tar, resin or shellac 2 and thus produce a moisture and as proof sheet whichcan be employed in t e manu: facture of containers. To this thickness I cement av second-thickness 3 by means of any desired cementsuchas ordinary glue 4, the

glue being applied to the surface of fused 4 material or to the surface of the other pl which is pressed against the fused material: It is obvious that the first ply may be propared in great rolls and then slitted preparatory to running the strips into a spiral winding machine such as is shown in my prior Patent No. 1,059,046, dated April 15, 1913, and that it or the second ply will be passed through a proper glue applying mechanism before it reaches the winding The glue will secure the two plies of the container together in the usual manner.

When the properties of the fusible Ina-'- terial and of the cement are such that the will not adhere, as when one is coated wit shellac' and the other with ordinary glue, I overcome the difficulty by dusting the surface 5 of the fusible material while still melted with some finely divided substance 6 to which the cement' l will adhere, powdered wood, grain and straw, finely divided cotton fibers and asbestos and neutral earths being suitable for such purpose.

It is to be understood that the cement that secures the two plies together is not necessarily a dissolved cement, for a fusible cement such as asphalt, gilsonite and petrolite may be employed, but for ordinar use,

glue dissolved in hot water will be ound satisfactory.

- I claim 1. A duplex board comprising one layer having one side coated with fused material and a second layer secured to the thus coated side of the first by means of a dissolved cement.

'2. A fibrous material having one side .coated with fused material whose surface isimpregnated with finely divided material to which cement readily adheres and a sheet of fibrous material secured b a dissolved cement to the fused. materia and to the coated with fused material whose surface is impregnated with finely divided wood and a sheet of fibrous material secured by a dissolved cement to the fused material and to the material with which the surface of said fused material is impregnated. .e 4. A duplex board comprlsing one pl having one side coated with fused material whose surface is impregnated with finely divided material to whlch cement readily adheres and a second ply secured to the thus coated side of the first ply by means of glue.

BEN KJFORDQ 

